hal: Add support for audio power policy handling

* Add PowerPolicyClient class to receive policy change notifications

* Add PowerPolicyClient launcher to join ABinder threadpool

* Add functionality to launch powerpolicy extn in a new thread

Change-Id: Ic9349ca7c94fe481b2d7a74536f97e32a7b0fe8e
Signed-off-by: Tahir Dawson <dawson@codeaurora.org>
diff --git a/hal/audio_hal_plugin.h b/hal/audio_hal_plugin.h
index 3d77b23..1f56a2f 100644
--- a/hal/audio_hal_plugin.h
+++ b/hal/audio_hal_plugin.h
@@ -87,6 +87,7 @@
     AUDIO_HAL_PLUGIN_MSG_CODEC_GET_PP_EQ_SUBBANDS, /**< get EQ subbands params */
     AUDIO_HAL_PLUGIN_MSG_CODEC_TUNNEL_GET_CMD, /**< pass through get cmds */
     AUDIO_HAL_PLUGIN_MSG_SILENT_MODE, /**<set silent boot mode */
+    AUDIO_HAL_PLUGIN_MSG_MIC_STATE, /**< enable or disable codec mic */
     AUDIO_HAL_PLUGIN_MSG_MAX
 } audio_hal_plugin_msg_type_t;